FAA Aviation Mechanic Airframe (AMA)Landing Gear SystemsHard
An anti-skid braking system uses a component mounted at each main wheel to sense the wheel's rotational speed and send an electrical signal to the anti-skid control box. If this component fails, what is the most likely result?
- AThe nose wheel steering will disengage automatically
- BThe landing gear will fail to retract after takeoff
- CThe affected wheel's brake may not receive proper anti-skid modulation, risking a skid or lockup
- DThe parking brake will not release
Show answer & explanationAnswer & explanation
Correct answer: C. The affected wheel's brake may not receive proper anti-skid modulation, risking a skid or lockup
The wheel speed transducer (tachometer generator) at each wheel provides speed data to the anti-skid control unit; if it fails, the control unit cannot properly detect an impending skid at that wheel, and anti-skid protection for that brake may be lost or malfunction, risking a wheel lockup or skid.
Why the other options are wrong
- A. Nose wheel steering is a separate system unrelated to main wheel speed sensors.
- B. Gear retraction is controlled by hydraulic/mechanical systems, not by anti-skid wheel speed sensors.
- D. The parking brake system is typically independent of the anti-skid wheel speed sensors.
Wheel Speed Transducer
A sensor mounted on each braked wheel that generates an electrical signal proportional to wheel rotational speed, used by the anti-skid control unit to detect impending skids.
- Located at each main gear wheel with anti-skid
- Sends speed signal to anti-skid control box
- Failure can cause loss of skid protection at that wheel
Memory trick: 'The wheel's own speedometer tattles to the anti-skid brain'